1. Field of the Invention
The present invention relates to an accelerator pedal device.
2. Description of the Related Art
U.S. Pat. No. 6,070,490 discloses an accelerator pedal device that includes a pedal reaction force spring for generating a reaction force against an accelerator manipulation force applied to an accelerator pedal and a hysteresis spring for generating a hysteresis load. The pedal reaction force spring and the hysteresis spring are separately formed. The accelerator pedal device further includes a hysteresis generating member and the like arranged only at one side of an accelerator pedal arm thereof.
The accelerator pedal device disclosed in U.S. Pat. No. 6,070,490 has problems as explained hereinafter.
The first problem is that, since the pedal reaction force spring and the hysteresis spring are formed as separate members, even if a malfunction occurs with respect to the operation of the pedal reaction force spring, only the hysteresis load remains, which results in giving discomfort to a driver in the return of the accelerator pedal.
The second problem is that, since the hysteresis generating member and the like are arranged only at one side of the accelerator pedal arm, it is feared that the load applied to an shaft of the accelerator pedal arm increases.
It is an object of the present invention to provide an accelerator pedal device which can considerably prevent the generation of discomfort in the accelerator manipulation and, at the same time, can prevent an excessively large load from being applied to an accelerator pedal shaft.
According to the present invention, there is provided an accelerator pedal device including an accelerator pedal arm, a liner, a hysteresis lever and a resilient member. The accelerator pedal arm is pivotally supported on a housing and tilted in response to accelerator manipulation. The liner is formed on the accelerator pedal arm in the vicinity of a pivoting point of the accelerator pedal arm. The hysteresis lever is resilient and is engaged with the housing to cross the accelerator pedal arm. The hysteresis lever includes a sliding portion slidable on the liner. The resilient member is interposed between a side of the accelerator pedal arm opposite to an applied point of an accelerator manipulation force with respect to the pivoting point of the accelerator pedal arm and a side of the hysteresis lever opposite to a portion engaged with the housing with respect to the sliding portion. The resilient member elongates and contracts in response to tilting of the accelerator pedal arm to generate a reaction force against the accelerator manipulation force and a hysteresis load due to sliding between the liner and the sliding portion.
The manner of operation of the accelerator pedal device is explained with respect to a case in which the accelerator pedal arm is manipulated by an accelerator pedal mounted on the accelerator pedal arm. When an accelerator manipulator steps on the accelerator pedal so as to tilt the accelerator pedal arm in a predetermined direction, the resilient member which is interposed between a given portion of the accelerator pedal arm and a given position of a hysteresis lever is contracted or elongated so that a reaction force which faces an accelerator manipulating force (a so-called pedal reaction force) and a hysteresis load are generated. Accordingly, the accelerator manipulator can have a reasonable moderation feeling at the time of acceleration and can maintain the accelerator pedal at a fixed position with a manipulation force smaller than a manipulation force necessary at the time of stepping-in the accelerator pedal when the accelerator pedal is to be maintained at the fixed position.
According to the accelerator pedal device, the resilient member is interposed between the accelerator pedal arm and the hysteresis lever which are arranged to cross each other. The interposed resilient member prevents an excessively large load from being applied to a pivoting portion of the accelerator pedal arm.
According to the accelerator pedal device, the resilient member which generates a reaction force (pedal reaction force) against an accelerator manipulating force and the resilient member which generates a hysteresis load are formed of the same member. Accordingly, even if a malfunction occurs with respect to the operation of the resilient member, both of the pedal reaction force and the hysteresis load which act in the directions opposite to each other can be cancelled or decreased so that large discomfort in the return of the accelerator pedal hardly occurs as much as possible.